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    Effects of operating a solar air heater on the indoor air quality in classrooms during the winter : a case study of Palmerston North primary schools : a thesis submitted in partial fulfilment of the requirements for the degree of Doctor of Philosophy (PhD) in Building Technology at Massey University, Auckland, New Zealand
    (Massey University, 2020) Wang, Yu
    Schools are densely populated places, where children spend a large amount of their time. The indoor air quality (IAQ) in classrooms impacts students’ health, academic outcomes and school absences (Borras-Santos et al., 2013; Mi et al., 2006; Shendell, Prill, et al., 2004; Smedje and Norbäck, 2000; Taskinen et al., 2007). Three New Zealand (NZ) studies have found low ventilation rates, low temperature levels, high relative humidity (RH) levels and high carbon dioxide (CO2) levels during the winter months in NZ primary schools (Bassett and Gibson, 1999; Cutler-Welsh, 2006; McIntosh, 2011). These results show a need to improve the indoor environment in NZ schools during the winter. NZ school hours, from 9 am to 3 pm, are well aligned with the optimum solar radiation and classrooms lend themselves to heat from solar energy. A project was undertaken to investigate if operating a roof-mounted solar air heater (SAH) could improve the classroom IAQ during the winter. This two-year crossover project was undertaken in four Palmerston North (PN), NZ primary schools in 2013 and six PN, NZ primary schools in 2014. These consisted of the four schools participated in 2013 plus two additional schools. In each school, two adjacent classrooms with similar construction characteristics and population characteristics participated in this project. The two adjacent classrooms were randomly assigned either to a treatment group (SAH installed and operated) or to a control group (SAH installed but not operated). The main objective of this project was to investigate the change in levels of the classroom temperature, RH, CO2, and ventilation rate from when a roof-mounted SAH was operating (treatment) and was not operating (control). Resulting from operating the roof-mounted SAH, the temperature in treatment classrooms was on average 0.5 °C higher than in the control classrooms, when both the control and treatment classrooms had the same heater use. When the control and treatment classrooms achieved the same temperature, the heater use in the treatment classrooms was 27% less than the heater use in the control classrooms. Across all schools, CO2 levels in the treatment classrooms were on average 96 ppm lower than in the control classrooms. In five out of 10 schools (50%), the levels of CO2 in the treatment classrooms were lower than in the control classrooms. Only in one treatment classroom did the ventilation rate meet the NZ Ministry of Education recommended level of 4 air changes per hour. Overall, operating a roof-mounted SAH played a positive role in increasing the temperature and ventilation rate in classrooms during the winter. However, there was not sufficient airflow to satisfy the ventilation requirements. Future research should investigate the impact of operating a SAH on the school ventilation and temperature considering increasing the SAH outlet air volumetric flow rate and keeping the outlet air temperature around 18 °C to bring more heated air into classrooms.
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    Improving heating plant emissions using flue gas carbon monoxide monitoring : a thesis presented in partial fulfilment of the requirements for the degree of Masters of Engineering in Automation and Control at Massey University
    (Massey University, 2011) Al Shukairi, Jokha Hamood
    RCR Energy Systems builds industrial heating plants and their control systems. In these the excess air (above the stoichiometric ratio) for combustion is a process variable and its setpoint is determined using a look-up table. RCR aims to improve the efficiency of wood-fired, thermal-oil heating plants by using a combination of carbon monoxide monitoring and oxygen trim control to automatically adjust the excess air setpoint. Heating plants require the correct amount of oxygen for combustion. Too little excess air does not allow complete combustion, producing a loss in efficiency and wasted fuel. Too much excess air reduces the flame temperature with a consequent drop in heat transfer rate and loss of efficiency. The aim of the project was to explore the advantages of carbon monoxide monitoring and oxygen trim control, as well as its application, design and implementation in trimming excess oxygen setpoint, to a lower, but still safe operating level. Various carbon monoxide monitoring and oxygen trim control schemes were researched with the most suitable being implemented on an industrial system using a combined carbon monoxide and oxygen measurement analysers. This scheme was then tested on the heating plants at Hyne & Son in Tumbarumba, Australia. The tests proved that the excess air setpoint could be successfully reduced by 2%, leading to an approximate 3 – 5% improvement in efficiency.
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    Development of a decision support system for the design of good indoor air quality in office buildings : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Product Development at Massey University, Turitea, New Zealand
    (Massey University, 2001) Phipps, Robyn A.
    Office buildings are complex entities. Design decisions can affect the quality of the indoor air (IAQ) throughout the life of the building. Poor IAQ affects approximately 30% of all office buildings and is ranked within the five greatest risks to human health in developed countries. Despite a vast and growing body of scientific literature on IAQ, there is a large gap between the current knowledge and the application of this knowledge in building practices. The USA Environmental Protection Agency identified a high priority need for design and educational tools to assist building designers who are not experts in IAQ issues to create healthy buildings. In this study a Decision Support System (DSS) for the design of good IAQ in office buildings was developed. The DSS leads building designers through a structured question database on building attributes that affect IAQ. Full justification for each design decision is given in order to prompt designers to select building features that lead to low indoor concentrations of volatile organic compounds, gaseous pollutants, microbiological contaminants and respirable particulates. The DSS was developed for new office buildings in New Zealand conditions, with either natural or mechanical ventilation. An exisiting methodology for the development of DSS was used. The problem was approached from the perspective of the building users under the broad headings of site and external factors, building envelope, building infrastructure, interiors, and heating ventilating and air-conditioning. Each of these topics was subdivided into finer layers of detail until conclusions on the potential impact of each building element on the IAQ could be inferred. The hierarchy for decision-making placed highest priority on the elimination or reduction of pollutants at source. Opportunities for pollutants to enter from outside or spread within the building were also controlled. If either of these strategies were not found acceptable, then mitigation techniques were recommended. A panel of independent national and international experts validated the DSS for correctness and completeness. The reviewers reported that the system was very comprehensive, drew correct conclusions and would assist building designers without IAQ expertise, to design office buildings with good IAQ. The DSS was also considered to have a significant educational component for users.